N DEPARTMENT OF THE INTERIOR 

UNITED STATES GEOLOGICAL SURVEY 

GEORGE OTIS SMITH, Director 

J , Bulletin 365 


FRACTIONATION OF CRUDE PETROLEUM 

BY CAPILLARY DIFFUSION 

» ' i \- ’‘ 

■ ' ^ ' ■■ ■ . It ‘ '%< ■ k* > v ■ vv - >' . ’■' *r J 

'A; ^■ V '^'■ ' ? 'LW. ='• •• W • 

BY ■ ; 

J. ELLIOTT GILPIN and MARSHALL P. CRAM 

UNDER THE SUPERVISION OF 

DAVID T. DAY 


WASHINGTON 

GOVERNMENT PRINTING OFFICE 

1908 




THE 















Glass_~J K 8 T1 

Book_ -G 6_ 







n * 


department of the interior 


UNITED STATES GEOLOGICAL SURVEY 

t 

GEORGE OTIS SMITH, Director 

— 

BULLETIN 365 


vy- /7 

e / 


tut 


j 




BY 

J. ELLIOTT GILPIN and MARSHALL P. CRAM 

u 

UNDER THE SUPERVISION OF 

DAVID T. DAY 



WASHINGTON 

GOVERNMENT PRINTING OFFICE 

19 08 

Co Yy -U 


v* 








14 =' 


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CONTENTS. 


Page. 

Introduction. 5 

Detailed description of experiments... 6 

Fractionation in tubes. 6 

Water fractionation. 28 

Oil lost in the fuller’s earth.!. 30 

Fractionating power of substances other than fuller’s earth. 32 

Summary. 33 


ILLUSTRATIONS. 


Page. 

Fig. 1. Curves showing proportion of hydrocarbons soluble in sulphuric acid, 

oils 1 and 2. 24 

2. Curves showing proportion of hydrocarbons soluble in sulphuric acid, 

oils 3 and 4. '25 

3. Curves showing proportion of hydrocarbons soluble in sulphuric acid, 

oils 5 and 6. 26 


3 


















THE FRACTIONATION OF CRUDE PETROLEUM BY 

CAPILLARY DIFFUSION. 


By J. Elliott Gilpin and Marshall P. Cram. 


INTRODUCTION. 

When, in process of refinement, black vaseline is filtered through 
warm, dry fuller’s earth, the first product is an oil that is perfectly 
liquid at ordinary temperatures, but the succeeding portions are 
progressively more viscous until fairly hard vaseline is obtained. 
The observation that a fractional separation of oils in vaseline had 
been effected suggested to David T. Day that a like result might be 
obtained with crude petroleum. He applied this method to a sample 
of green crude petroleum from the “third sand” of Venango County, 
Pa., and found that light products, chiefly gasoline, first appeared 
when such crude oil was allowed to filter down through a long glass 
tube filled with granulated or powdered fuller’s earth.® 

This result was followed by experiments with a more elaborate 
system of specially constructed funnels similar to those used by the 
refiners of vaseline in testing the comparative value of various fuller’s 
earths. The results from these experiments were briefly summarized 
in a paper on the ability of petroleum to migrate in the earth. 6 
Engler later verified these results and showed that the separation 
was mechanical and that no oxidation was effected in the process. 
Day next used a large closed funnel of galvanized iron holding about 
100 pounds of fuller’s earth. When crude petroleum was dropped 
slowly and regularly into this funnel, rather light oils were obtained 
at first, followed by the usual succession of heavier oils. As it was 
evident from this work that much of the oil passed through crevices 
without any change, Day tried the effect of reversing the route of 
the oil and of allowing it to diffuse upward through a tube packed 
tightly with fuller’s earth. In such a tube the lighter constituents 
rose much more rapidly than the more viscous oils, so that by separat- 


a Proc. Am. Philos. Soc., vol. 36, No. 154, 1897. 


b Trans. Petroleum Congress (Paris), 1900. 









6 


FRACTIONATION OF CRUDE PETROLEUM. 


ing the fuller’s earth from different sections of the tube and displacing 
the oil by water, very different oils were obtained from the upper 
and lower parts of the tube. 

By using several tubes and uniting oils of the same specific gravity 
oil of different grades can be collected in sufficient quantity to be 
fractionated again, and the process can be continued until oils result 
which are not altered by further passage through tubes filled with 
fuller’s earth. At the suggestion and with the cooperation of Doctor 
Day we have taken up this problem with the results here stated. 

DETAILED DESCRIPTION OF EXPERIMENTS. 


FRACTIONATION IN TUBES.' 


The tubes used first were of glass, 3 feet long and 1£ inches in 
diameter. They were closed at the lower end with corks along 
whose sides six or seven grooves had been cut, the inner end of the 
cork being covered with a bit of cotton cloth to prevent the earth 
from sifting out through the grooves. Such tubes filled with fuller’s 
earth were placed with their lower ends in an open dish of petroleum 
and the oil w r as allowed to rise. 

At room temperatures (18° to 22° C.) and atmospheric pressure, 
the rate of rise of crude petroleum in a tube filled with fuller’s earth 
was very slow. In seven days the oil ascended but 73 centimeters 
in one tube and 59 centimeters in another, and in a third tube ten 
days were required for it to rise 59 centimeters. To study the 
effect of heat, a glass tube about 3 feet long and 1 J inches in diameter 
was filled with earth and placed in a bottle holding about 2 liters of 
oil, and the wdiole was heated by an electric stove with which tern- 
peratures considerably above those of the room could be maintained 
day and night. The temperature of the tube was kept between 40° 
and 70° for three days, in which time the oil rose 54.7 centimeters in 
the tube; in another tube packed in all ways like the first, but held 
at room temperature (about 20°), the oil rose 46 centimeters in the 
same length of time. With two tubes in which the earth was packed 
much less compactly the time required for the oil to rise 54 centi¬ 
meters was four days for the tube at room temperature and two days 
for the one at 50° to 80°. The rate of rise was evidently but little 
affected by heat, at least within this range of temperature, and higher 
temperatures could not be used without loss of the more volatile 
constituents of the oil. 

The next attempt at increasing the rate of rise of the oil consisted 
in applying diminished pressure to the top of the tube, which reduced 
the time required for the oil to reach the top of a tube 5 feet long 
from several weeks to seventeen hours. If diminished pressure is 


FRACTIONATION IN TUBES. 


7 


continued after the oil has reached the top and if the oil is not 
exhausted in the reservoir at the bottom, oil will be drawn over from 
the top of the tube. The specific gravity of the oil thus collected 
steadily rises as it comes over. The samples so obtained, however, 
stand under very low pressures for some time, which may cause a 
loss of their more volatile constituents. This suggested applying 
increased pressure to the oil in the reservoir rather than diminished 
pressure to the top of the tube, and an iron bomb, like those used for 
the transportation of mercury, was fitted with an iron pipe 7 feet 
long to contain earth and a side arm at the bottom of the bomb to 
which a water column might be attached. 

The bomb, which held about 2 liters, could be partly filled with 
petroleum and the pipe containing the earth screwed into the top. 
The side arm which opened into the bottom of the bomb could then 
be connected with the water pressure so that the lower part of the 
bomb was filled with water which drove the petroleum upward. 
The oil obtained at the top, however, was fractionated no further 
nor in any larger amounts than when the oil was not allowed to 
emerge from the top of the tube. The difficulty of setting up such a 
pressure apparatus with tight connections, as well as the range of 
pressure required—a column of water 7 feet high being too great when 
the oil was just started up the tube and a column 30 feet high being 
insufficient when it was near the top—made its use impracticable. 

To use diminished pressure, the earth in the tubes must not be 
packed so hard that the air just above the oil can not be drawn 
through the earth above, nor must the earth be packed so loosely that 
the oil will rise as in a vacuum. The right degree of hardness is 
obtained by filling about 1 foot of the tube at a time and packing that 
much earth as hard as possible with a wooden rod tipped with a 
rubber stopper. If the tube when pounded on the floor rings in the 
hand, it indicates that the earth may be packed too closely. Tubes 
may be packed much more easily by filling several at once, with a 
separate ramrod for each. By allowing a few minutes to elapse 
between successive liftings of the ramrod, much labor is avoided. A 
bit of cotton waste below a rubber stopper at the top of the tube will 
prevent any earth from being drawn up when the air is exhausted. 

The fuller’s earth was first heated in shallow iron pans until it 
ceased to form geysers when stirred. The earth must be thoroughly 
cold before it is packed into tubes, or the contraction will be sufficient 
to allow the oil to run up the tube immediately when the air is 
exhausted. 

Much trouble was experienced with the tubes first used on account 
of their breaking—not when in service, but soon afterward. This was 
thought to be due to the age of the tubing, but the same tiling hap- 


8 


FRACTIONATION OF CRUDE PETROLEUM. 


pened with new tubes 5 feet long and 1} inches in diameter. With 
the idea that the iron scraper used to remove the earth from the tubes 
might be the cause, a scraper entirely of wood was tried, but this did 
not decrease the breakage, it being notliing unusual on going to the 
laboratory in the morning to find that half of the tubes which had 
been emptied the day before were cracked. 

It had been considered necessary to use tubes of glass in order that 
the height to which the oil had risen could be seen and that in remov- 
ing the oil from the middle of the tube it might be scraped out to a 
sharp dividing line, as the level to which the oil has risen is the point 
from which should be made all measurements of sections into which 
the tube is to be divided. Tin tubes were used later to avoid the 
trouble experienced with glass tubes. These tin tubes were emptied 
by shaking the earth from the bottom into four 30-centimeter cylin¬ 
ders of the same diameter as the tube, these cylinders being made of 
two curved pieces of tin held together by a cap at one end and a ring 
at the other. The cylinders containing the contents of the tube 
could be opened lengthwise and the earth divided into any desired 
lengths. Two glass tubes 5 feet long and 1J inches in diameter were 
set up in the same dish of petroleum with ten or twenty tin tubes 5J 
feet long and of the same diameter as the glass tubes, and when the 
oil stood at the top of the glass tubes the tin ones were also opened. 
Glass tubes, of course, can be emptied as well as tin tubes by shaking 
the contents from the bottom, and there was no more breakage after 
this method was adopted. 

The level to which the oil will rise can be regulated by the amount 
of oil in which the tube is placed, and in the later work the adop¬ 
tion of this method did away with the use of glass tubes entirely. In 
a tube lj inches in diameter and 5J feet long 950 cubic centimeters 
of oil will rise within 20 to 35 centimeters of the top. 

When the oily earth has been removed from the tube, the oil may be 
separated by adding water. In the first experiments enough water 
was added to form a very thin mud, which was thoroughly stirred 
by a small propeller driven by a water motor. The mixed earth, oil, 
and water were then poured into a large separating funnel and allowed 
to stand several minutes until the oil had collected at the top. The 
earth and water could then be drawn off and the pure oil left. 

It was found later, however, that if less water is added to the earth 
as removed from the tubes, after standing a few minutes all the water 
will pass into the earth and this will be accompanied by the libera¬ 
tion of oil. Oil so liberated can then be poured off directly from 
the earth without the labor of churning. When water first begins to 
liberate oil, the earth is granular; but when more water has been added 
and the last of the oil recovered, the earth has the consistency of a 


FRACTIONATION IN TUBES. 


9 


thin paste that will flow when the dish is inclined, which it will not 
do when the oil begins to come off. 

All the oil from one section of a tube is of the same color irrespec¬ 
tive of whether it is the first or the last oil to come off when water is 
added. It was assumed at first that all the oil which came from one 
section of earth had the same specific gravity, but this was found later 
not to be the case. The first oil to be collected, if taken in sufficiently 
small volume, say about 20 cubic centimeters, is slightly heavier than 
the next portion. If as much as 100 cubic centimeters is included in 
the first sample, however, this will not be true. Beginning with the 
second sample the successive portions of oil steadily increase in spe¬ 
cific gravity, the gradual addition of water affording another means 
of fractionation in addition to the separating power of the earth. 
Both of these methods of separation have been combined in this 
investigation. The earth must be thoroughly mixed after each addi¬ 
tion of water to prevent a layer of water-wet earth from isolating 
earth that contains oil from the water added. 

The petroleum used was a dark-green oil from Venango County, Pa., 
of specific gravity 0.810. When 950 cubic centimeters of this oil was 
drawn upward in a tin tube 51 feet long, the following separation 
was obtained: 


Table 1 . —Fractionation of crude petroleum in single tubes. 


Time required, in hours. 

Distance from top of tube to oil when 
opened, in centimeters. 


A, 8 centimeters at top 

B, next 8 centimeters.. 

C, next 18 centimeters. 

D, next 30 centimeters. 

E, next 35 centimeters. 

F, rest. 


1. 

2. 

3. 

23.5 

17.5 

17.5 

31 

28 

28 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

0. 796 

42 

0.8012 

30 

0.8022 

18 

.808 

45 

.804 

37 

.803 

35 

f . 8125 

75 

.807 

47 

. 8075 

06 

l .8137 

24 

.809 

22 

.810 

25 

.815 

130 

. 8125 

148 

.812 

140 

.818 

170 

.8185 

190 

.8175 

145 

.8205 

125 

.823 

100 

.821 

lao 


611 


574 


534 


The oil in grade C was collected in two portions, the second being 
obtained by the addition of more water after the flrst lot of oil was 
poured off. Although 950 cubic centimeters of crude petroleum were 
used in each experiment, it will be noticed that the oil recovered 
measures much less than that. When several tubes were worked up 
together, in one test 9,070 cubic centimeters of crude petroleum 
yielded 5,951 cubic centimeters of oil and in another 8,915 cubic 
centimeters gave 5,415 cubic centimeters. 

57714—Bull. 3G5—08-2 ' 






































Table 2. —First fractionation of crude 'petroleum. 


10 


FRACTIONATION 


OF CRUDE PETROLEUM. 


05 

2 glass, 7 tin. 

Glass, 8.5, 15; tin, 
58,31,60, 40, 16, 53, 
16. 

117. 

Cubic cen¬ 
timeters. 

175 

120 

180 

215 

300 

440 

100 

390 

400 

300 

200 

340 

240 

290 

350 

Specific 

gravity. 

----- A 

0.8025 1 
.8037 

.8042 

.8078 ; 

.809 

.8095 ! 

.8127 

.812 

.8137 

.8145 

.8155 

.818 

.8197 

.818 

.818 

cc 

2 glass, 7 tin. 

Glass, 0, 5; tin, 16, 
34, 28,15,18,23,10. 

48. 

Cubic cen¬ 
timeters. 

OO ICO OlOlO OQOON OQOOCj 

co co io co co r- oi oo © ■'* © — © co 't 

i-Ht- 4 T-iei 'COHN O 1.0 C) CC CO*OCO(N 

. W « 

Specific 

gravity. 

ia c) >on »o oo 

oo t-h c o ^ r- oo oo <M oi ^ r- co ^ ^ «-» 

05 O OO OOO 1-H • C l *—< *H rH H Cl H Cl 

oo oooo ooocoo oooooooooo ooocoooooo 

© 


2 glass, 7 tin. 

Glass, 0, 7; tin, 25, 
26, 23, 26, 28, 20, 28. 

84. 

Cubic cen¬ 
timeters. 

200 

115 

200 

200 

330 

430 

95 

425 

625 

360 

240 

650 

660 

300 

Specific 

gravity. 

0.800 

.802 

.8042 

.8048 

.808 

.8078 

.811 

.812 

.812 

.814 

.8172 

.816 

.8162 

.8195 

o 

2 glass, 8 tin. 

Glass, 0,12; tin, 30, 
28, 22, 30, 13, 12.6 

54. 

Cubic cen¬ 
timeters. 

1.0 © ©if? ©© ©IQIOW ©Q©*0 

© © T»1 o* © OO H Cl CC Cl to © CO O-l 

Ol HH COCQ COCC'l’i-l 00 CO cc 

Specific 

gravity. 

h- *0 CO *0 *0 

to to 1^0 O CO CO C N IO 0 

CD CO rH »-H rH Cl rH rH (M O'! 

00 00 00 00 00 00 00 00 00 00 00 00 00 00 

o 

*o 

2 glass, 7 tin. 

Glass, 0,6.5; tin, 26, 

1 28, 18,15, 28,12,24. 

24. 

Cubic cen¬ 
timeters. 

OO OO OO OOO 0*00 

OO OIOI COO CO Q O 00 <N O 

r-H rH rH HT CO lOCCl ^ CO 

Specific 

gravity. 

0. 804 
.8055 

.8085 

.811 

.8097 

.8122 

.813 

.8135 

.816 

.8162 

.8162 

.819 


2 glass, 8 tin. 

Glass, 0,15; tin, 40, 
15,24, 22,28,19, 24, 
32. 

54. 

Cubic cen¬ 
timeters. 

oo CC 00*0 0 *0*00 OOO 

*0*0 *0 Cfc CC^C O TJ1 o CO 

CO <N rH o ^ ^ oo 

Specific 

gravity. 

/ 0.8015 
\ .8005 

r .807 

t .810 

.809 

.809 

■ .810 

.8115 

.815 
.8145 
. 8175 

. 816 
• . 815 
.821 


Tubes . 

Distance from level of oil to top of tube, j 
in centimeters.® 

Time required, in hours.! 


A. 

B . 

C . 

D . 

E . 


The glass tubes are 5 feet long, the tin tubes 5£ feet. Both are 1} inches in diameter. 

Record of distance lost for two of the tin tubes. 

These fractions stood uncovered on top of the earth overnight, and consequently were exposed to considerable evaporation. 




















































































Table 2. —First fractionation of crude 'petroleum —Continued. 


FRACTIONATION IN TUBES. 


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»o o o 

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CM H 


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t— i »0 CM 
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»0 i.O »C CM 
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oooooooo oooooooo 


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Cl X »—< Cl "3 w rr CM l- X 


QQO 

TT«- 

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g& 

©*k! 

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p<g 


kO »0 X X ci »o o 
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»o »c 

CCOrHCM 

CC *“H r-< rH 

X X X X 


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tin . 

13; tin, 32, 
16, 48, 29. 


i 

Cubic cen¬ 
timeters. 

O O 
kO Tf 

r-H r-H 

0*0 0 

O O CM 

r-H t-H 

8SS 

rr cm 

8888 
^ ci 

o o o o 
o — oo 

CMkQ'Vn 

2 glass, 6 
Glass, 7, 
19, 32, 3 

3 

Specific 

gravity. 

0. 798 
.801 

CM CM 

ci o r - 

So 36 SB 

kO 
o ^h 

8 8 S3 

rH Oi r-H kO 

—• O rH ^ 

X X X X 

X 

kO »o n 

7-H rH r-H r-H 

X X X X 

tin. 

4; tin, 0, 0, 
17,7,5. 

Cubic cen¬ 
timeters. 

O O 

X X 

rH 

83 

CM rH 

8812 

X ^ r-H 

8888 
^ kO Cl CM 

O O kO o 

O Cl O I- 
TT* kO ^ X 


<*> ~© 
75 . 

73 73 ._r 
aj 73 ° 

’Sb-So 

<m O 




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05 bo 


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lO 
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X X 


o i—• rr 

rH 4 *-H 

XXX 


X X CM CM lO 

X X O''T NXCt^ 

rH r-H rH 1 —< 

X X X X 


X X 00 X 


tin, 40, 
7, 20, 27, 

• 

1 

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■9 E 

O O X 

O O CM 

CM h 

kO kO X 
cm ci 
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o »o o 

kO CM kC 

X kO r-H 

o o o o 

^roi'C 

^NXCl 

»Q O O kC 
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X N kO CM 

2 glass, 9 tin 
Glass, 0,8.5; 
32, 30, 26, Z 
25, 18. 

84. 

© *r* 

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Specific 

gravity. 

0.7995 
. 8037 
. 800 

kO CM 

X o ^ 

O — r-H 

XXX 

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rH rH rH 

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X O 
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rH rH rH rH 

X X X X 

NkOX 

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X X X X 




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o During the night, oil was drawn entirely through and out at the top of five tube's and so was lost. 

fc Three other tubes were set up with these, but when opened the oil in them was 81, 81, and 90 centimeters from the top, so they were discarded. This unevenness 
between the tubes was probably caused by using in some of them earth which was not entirely cold. 
c Beginning with lot 13 the pump was run continuously day and night. 
d The glass tubes are 5 feet long, the tin tubes 5$ feet. Both are li inches in diameter. 
































































































Table 2. —First fractionation of crude petroleum —Continued. 


12 


FRACTIONATION OF CRUDE PETROLEUM. 


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a Two reservoirs of crude oil were used in each of lots 18 and 19, but the earth from all 22 tubes was worked up together. Section D from all 22 tubes was first united and 
n, for convenience in working, divided into two portions. 

b The glass tubes are 5 feet long, the tin tubes 5J feet. Both are 1£ inches in diameter. 










































































FRACTIONATION IN TUBES. 


13 


To collect a sufficient quantity of oil, several tubes were placed in 
the same container of petroleum, two of the tubes being of glass and 
the rest of tin. When the oil had reached the top of the glass tubes 
all the tubes were opened, and the earth from the same level in all the 
tubes was mixed in tin pails. The oil was then liberated in several 
successive fractions by the addition of successive amounts of water. 
If the earth had been thoroughly mixed after each addition of water, 
the various oils from the same lot of earth would have increased 
regularly in specific gravity, instead of showing the variations which 
they did. For example, the first oil to be displaced by water in 
grades D and E of lot 4 (Table 2), with so large a volume, would not 
have been heavier than the succeeding oils if the water and earth had 
been thoroughly mixed before the oil was poured off. If we were to 
repeat the work, instead of using one common reservoir for all the 
tubes, we should use a separate reservoir for each tube, and open the 
tube when the oil in the reservoir was exhausted. This would do 
away entirely with the use of glass tubes, besides insuring that the 
level of the oil in each tube when opened would be practically the 
same. If a common reservoir is to be used, the tubes should all be 
packed with practically the same degree of hardness if the oil is to 
ascend in all with equal rapidity, as the ascent in all tubes is checked 
at the same time—that is, when the oil in the reservoir is exhausted. 

Diminished pressure was obtained by the use of a Chapman water 
pump, which reduced the pressure to 5 to 12 centimeters Hg., when 
connected with a system of tubes. In the earlier work the pump was 
not run through the night, which accounts for the much longer time 
required for these lots of tubes. 

The earth from a tube was divided into six sections, the level to 
which the oil had ascended in the tube being taken as the point to be 
measured from. A, the top section, included the 8 centimeters next 
the top; B, the next 8 centimeters; C, the next 18; D, the next 30; 
E, the next 35; and F what earth was left. F varied, of course, 
depending on the height to which the oil had risen. In fractionating 
the crude petroleum in bulk, F was usually discarded, as it was so 
viscous that it was deemed impossible to pass it through earth again. 
Records from several lots of tubes are given in Table 2. The specific 
gravity was measured with a Westphal balance, the temperature of 
the oil*being in every case exactly 20° C. Although the fourth decimal 
place is not to be taken as strictly accurate, yet it is considered worth 
while to record it as giving a nearer approach to the truth than would 
result from the use of only three decimal places. 

To study further the fractionation on addition of water, the oil of 
grade E from lot 16 was collected in fourteen fractions. The weight 
of the earth impregnated with oil before any water had been added 
was 13.5 pounds, and the weight of the earth containing all the water 
added, but minus the oil, was 17.5 pounds. The earth was placed in 



14 


FRACTIONATION OF CRUDE PETROLEUM. 


a galvanized-iron garbage pail and the water stirred in with an iron 
paddle. When the first portion of oil was liberated, the mass was 
of the consistency of bran, but as more water was added it turned to 
a fluid paste. When water was added and the pail inclined, oil would 
continue to drain out for half an hour or longer before the addition 
of more water became necessaiy. The oil which was liberated by 
one lot of water, therefore, could be collected in several portions, and 
this was done to see whether the oil which comes off immediately 
after the addition of water is the same as that which drains out 
later. The letters I, II, etc., indicate that the fractions included 
were liberated by one addition of water. 


Table 3. —Fractionation of oil of grade E, lot 16 , Table 2 . 



Specific 

gravity. 

Cubic 

centi¬ 

meters. 


Specific 

gravity. 

Cubic 

centi¬ 

meters. 

I. 

0.821 

25 

TV 

f 0.8208 

575 





I . 8222 

55 


f .818 

70 




II. 

\ .818 

70 

v 

f .824 

170 


[ .8193 

250 


\ .828 

16 


.818 

395 

VT 

f .827 

95 


.818 

350 

V 1...... 

t .830 

45 

Ill. 

.818 

460 





.820 

60 





The first fraction is regularly of higher specific gravity than those 
immediately following if only enough water is added to liberate a 
first fraction of small volume, say about 20 cubic centimeters. As 
the fraction first obtained becomes larger in volume, it approaches 
nearer to the second fraction in specific gravity, and will even fall 
below that fraction if the volume is made too large. 

The range of specific gravity covered by this first fractionation of 
the crude petroleum of specific gravity 0.810 was from 0.800 to 0.830. 
Fractions of the same specific gravity and of the same grade were 
united and the products chilled and filtered to remove all the dis¬ 
solved paraffin possible. This was done out of doors toward the last 
of December, when the thermometer stood at about 4° to 8° C. 
Lower temperatures would not only throw paraffin out of solution, 
but cause the whole oil to thicken. The oils were filtered through 
large plaited filters of drying paper, twenty-four hours or more being 
required for many of the filters to empty completely. The lighter 
oils in sections A and B deposited no paraffin. Some of the heavier 
grades deposited as much as 10 per cent of their weight, accompanied 
in many cases by a slight change in specific gravity. 

When these oils were filtered through earth again they behaved as 
shown in Table 4. As before, 950 cubic centimeters of each oil was 
used and the tube was divided into five sections, A being the top 8 
centimeters, B the next 8, G the next 18, D the next 30, and EF the 
rest. 





























Fractionation in tubes 


15 


Table 4.— Second fractionation. 

[Note. —Nine hundred and fifty cubic centimeters were needed for each tube, and for many tubes this 
amount was available of the same grade (A, B, C, etc.) and of the same specific gravity. For some 
tubes, however, it was necessary to unite oils of the same grade which differed slightly in specific gravity. 
No such samples differed by more than 0.0015 and all are marked with an asterisk (*) in the table.] 


* 

20 (A, 0.8015). 

21 (A, 0.806). 

*22 (B, 0.805). 

23 (B, 0.8055). 


Specific 

gravity. 

Cubic 

centime¬ 

ters. 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

A. 

0.8012 

36 

0. 803* 

45 

0. 7997 

50 

0.8005 

45 

B. 

.800 

44 

.8035 

48 

.802 

50 

.8033 

48 

c, . . 

f .8012 
[ . 8027 

.8022 

68 

35 

170 

.8035 

.8052 

.805 

78 

28 

160 

. 8055 

108 

.805 

115 

D . 

. 8063 

175 

.8063 

180 

EF. 

.8047 

330 

.807 

320 

.808 

260 

.8085 

260 











683 


679 


643 


648 


24 (B, 0.8065). 

25 (B, 0.809). 

*26 (B, 0.8105). 

*27 (B, 0.812). 

A . 

0. 8077 

38 

0. 8013 

45 

0.8075 

38 

0.8105 1 

42 

B . 

.807 

50 

.805 

50 

.8085 

50 

.8105 

42 

C . 

f .808 
^ . 8092 

80 

.807 
.810 
. 8095 

75 

30 

180 

. 8105 

100 

.8085 | 

.810 

.8115 

73 

22 

D . 

160 

. 8125 

160 

140 

EF. 

.8115 

300 

.8115 

350 

.8133 

275 

.8145 

250 












628 


730 


523 


569 


28 (C, 0.8095). 

29 (C, 0. 810). 

30 (C, 0. 811). 

*31 (C, 0. 811). 

A . 

0. 805 

52 

0. 8035 

40 

0.8005 

50 

0.803 

50 

B . 

C . 

D . 

.8065 
f .8085 
\ .811 
( .811 

52 

70 

28 

160 

.808 
.810 
. 8115 
.8115 

40 

75 

30 

140 

/in 

.809 

.812 

.813 

38 

115 

175 

.808 

.813 

. 8135 

55 

105 

180 

EF . 

l 

.813 

350 

• oloO 

.813 

350 

.8145 

310 

.8155 

300 












712 


715 

_ 


688 

_ 


690 


32 (C, 0.8115). 

33 (C, 0.813). 

*34 (C, 

0.8135). 

*35 (C, 0.8135). 

A . 

0. 806 

45 

0.8072 

20 

0.803 

42 

0.8025 

35 

B . 

.807 

35 

.811 

35 

.810 

53 

100 

.8077 

35 

c . 

.810 
.812 
.812 
.813 
.813 
.8135 
. 813 

60 

OO 

.812 

.813 

.8145 

.815 

.8155 

. 8155 

.818 

70 

25 

90 

80 

200 

125 

35 

.813 

. 8135 

100 

D . 

oo 

70 

07 

.815 

150 

.8145 

160 

F, F . 

103 

105 

50 

.817 

300 

.817 

325 


.813 

47 
a 63 









708 


680 


645 


655 


36 (C, 0.815). 

*37 (C, 0.81551. 

*38 (C, 

0.8155). 

*39 (C, 0.8165). 

A . 

0. 805 

43 

0.8053 

50 

0. 808 

40 

50 

100 

165 

290 

0.808 

.8145 

.816 

.8175 

.820 

50 

50 

82 

* 125 

310 

B . 

.8105 

40 

.812 

45 

. 8095 

c . 

.814 

98 

.816 

103 

. 8135 

b . 

.815 

155 

. 8175 

160 

.817 

EF. 

.817 

280 

.819 

310 

.819 

• 


616 


668 


645 


617 


a Unused. 





































































































































































16 


FR ACTIO NATION OF CRUDE PETROLEUM 


Table 4. —Second fractionation —Continued. 



*40 (D, 0.8135). 

41 (D, 0.814). 

42 (D, 0.814). 

43 (D, 0.814). 


Specific 

gravity. 

Cubic 

centime¬ 

ters. 

Specific 

gravity. 

Cubic 
centime- 
* ters. 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

A . 

0.8095 

45 

0.8045 

30 

0.806 

32 

0.806 

25 

B.I 

. 8085 

45 

.8115 

45 

.811 

45 

.8097 

30 


| .811 

95 

.8135 

75 

.813 

92 

.814 

50 


1 


.8165 

28 





D .I 

.8155 

165 

.818 

140 

.8175 

140 

.8157 

145 

F F 

.817 

320 

.821 

300 

.8195 

310 

.8175 

400 



670 


618 


619 


650 


44 (D, 0.814). 

45 (D, 0.814). 

46 (D, 0.8145). 

47 (D, 0.815). 

A. 

0.8008 

45 

0.800 

50 

0.808 

45 

0.800 

42 

B. 

.8077 

50 

.8065 

55 

.8115 

40 

.807 

47 


f .814 

103 

.8125 

100 

.8135 

65 

.814 

110 

C. 

\ 




.8155 

30 




f .8175 

160 

.816 

160 

.817 

105 

.816 

150 

1). 

\ 




.818 

58 




( .819 

310 

.817 

300 

.8195 

180 

.819 

330 

EF. 





. 8202 

120 




i 




.821 

53 





668 


665 


696 


679 

48 (D, 0.815). 

49 (D, 0.8155). 

50 (D, 0.8155). 

51 (D, 0.8155). 

A. 

0. 810 

37 

0. 8045 

40 

0. 8105 

45 

0.8058 

40 

B. 

.805 

47 

.811 

48 

.8148 

47 

.810 

40 


.812 

105 

.815 

98 

.810 

100 

.8132 

60 

C. 







.8145 

50 


.817 

160 

.8185 

160 

.815 

140 

.8172 

75 

D. 







.8188 

55 








.8188 

38 


.819 

300 

.820 

310 

.819 

400 

.820 

38 








.819 

100 








.8208 

30 

EF. 







.8208 

45 








.8208 

30 








.8208 

95 









a 40 



649 


656 


732 


736 



52 (D, 0.816). 

*53 (D, 0.816). 

54 (D, 0.8165). 

55 (D, 0.8165). 

A. 

0.806 

38 

0.803 

43 

0.806 

47 

0.8095 

42 

B. 

.8115 

42 

.8105 

30 

.811 

48 

.8135 

40 


f .814 

70 

.815 

100 

.815 

98 

.8145 

77 


\ .8175 

25 







D. 

.8185 

125 

.8185 

175 

.8188 

150 

.8188 

150 

EF. 

.821 

300 

.820 

290 

.8208 

300 

.821 

295 



700 


638 


643 


604 


*56 (D, 

0.8165). 

*57 (D, 

0.817). 

*58 (D, 0.818). 

59 (D, 0.8187). 

A. 

0.806 

45 

0. 8075 

40 

0.808 

45 

0. 811 

40 

B. 

.810 

45 

.8115 

40 

.8135 

45 

.812 

45 

C. 

.8145 

95 

.815 

100 

.817 

105 

.814 

92 

D. 

.8185 

160 

.818 

130 

.820 

150 

.819 

150 

EF. 

.821 

295 

.821 

330 

.822 

300 

.823 

305 



640 


640 


645 


632 


a Unused. 


























































































































































FRACTIONATION IN TUBES 


17 


Table 4 .—Second f ractionation — Continued. 



*60 (D, 0.8205). 

61 (E, 0.814). 

*62 (E, 0.8163). 

*63 (E, 

0.817). 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

A. 

0. 8045 

45 

0. 8075 

33 

0. 8155 

42 

0.804 

45 

B. 

.813 

45 

.810 

35 

.808 

50 

.8075 

50 

c 

f . 8175 

90 

.8125 

80 

.8095 

70 

.8145 

102 


l 




.812 

25 



D 

f .822 

170 

.818 

125 

.8175 

105 

.8205 

150 


l 




.8182 

32 



EF 

1 .823 

270 

.8245 

300 

.823 

2.50 

.8245 

300 


l 

o 70 



.8255 

41 





692 


573 


615 


647 


*64 (E, 0.817). 

*65 (E, 0.818) .a 

*66 (E, 0.818). 

67 (E, 

0.818). 

A 

/ 0.805 

42 

0. 8065 

90 

0.805 

38 

0.805 

40 


l 


.809 

20 





B. 

.810 

42 

.810 

110 

.811 

38 

.811 

45 

n 

f . 8145 

75 

.8155 

186 

.8135 

104 

.8145 

85 


1 


.817 

50 





T) 

] .820 

135 

. 8205 

385 

.819 

175 

.8185 

125 


l 


.8205 

75 





FF 

( .8255 

235 

.8255 

650 

.8235 

240 

.824 

325 


1 


.8255 

260 







529 


1,826 


695 


620 



*68 (E, 

0.8185). 

69 (E, 0.819). 

70 (E, 0.819). 

*71 (E, 0.819). 

A. 

0. 8205 

15 

0. 804 

24 

0. 8115 

21 

0. 8005 

23 

B. 

. 8043 

35 

. 808 

40 

. 814 

31 

. 8085 

34 

c. 

/ .810 
\ .812 
.817 

60 

30 

160 

.8145 

85 

.815 

90 

.814 

80 

D. 

. 8195 

140 

.8165 

120 

. 820 

160 

EF. 

.8225 

300 

.824 

330 

.824 

330 

.824 

280 




590 


589 


592 


577 


*72 (E, 0.8195). 

*73 (E, 

0.8195). 

74 (E, 0.8195). 

75 (E, 

0.8197). 

A. 

0.8145 

30 

0.8055 

34 

0.816 

40 

0.8025 

40 

B. 

.8105 

42 

.811 

45 

.8135 

42 

.8105 

38 

C. 

/ .8135 

103 

.8155 

80 

.809 

.814 

.8185 

65 

34 

160 

.816 

90 

D. 

l 

.8195 

160 

.820 

120 

.822 

150 

EF. 

f .824 

285 

.824 

290 

.824 

.827 

260 

30 

.8255 

300 


l 








620 


569 


631 


618 


A. . 

B. . 

C. . 

D. . 

EF 


*76 (E, 0.820). 


0.8045 
.812 
.817 
.822 
.826 


48 

40 

91 

155 

260 


594 


*77 (E, 0.8205). 


0.806 
.8125 
.8175 
.823 
. 8245 


32 

45 

90 

100 

330 


597 


78 (E, 0.8215). 


*79 (E, 0.S22). 


0.8045 
. 8135 
.8185 
.823 
.8275 


28 

36 

78 

150 

300 


592 


0.8105 
.8145 
.819 
.8225 
.827 


32 

42 

77 

155 

280 


586 


a Three tubes. 

57714—Bull. 3G5—08-3 

























































































































































18 


FRACTIONATION OF CRUDE PETROLEUM 


Table 4 .—Second fractionation —Continued. 



80 (E, 

0.822). 

81 (E, 

0.822). 

82 (E, 

0.824). 

*83 (A-B, 0.804). 

Sp eific 
gravity. 

Cubic 

centime¬ 

ters. 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

Specific 

gravity. 

Cubic 

centime¬ 

ters. 

A. 

0.817 

30 

0.8083 

26 

0.8125 

48 

0.803 

32 

B. 

.810 

40 

.814 

40 

.8127 

48 

. 8035 

25 


f .8153 

46 

.8185 

92 

.818 

53 

.8035 

63 


l . 8163 

42 



.819 

50 



D. 

.8225 

1(K) 

.824 

140 

.8245 

175 

.804 

140 


1 .8265 

295 

.8265 

270 

.828 

200 

.806 

275 

EF. 





.830 

90 




1 





« 50 





613 


568 


714 


535 


*84 (A-B, 0.8065). 

*85 (A-B, 0.808). 

* 86 (B-C- 

D, 0.8125). 

* 87 (B-C-D ,0.8125) .5 

A. 

0.8035 

40 

0.8085 

30 

0.805 

32 

0.805 

80 

B. 

.8055 

40 

.807 

30 

.808 

42 

.8085 

73 


/ .809 

80 

.8065 

92 

.813 

85 

.812 

118 


i 






.813 

75 

D. 

.8085 

155 

.8085 

115 

.815 

175 

.815 

285 

EF. 

.811 

300 

.8115 

330 

.820 

280 

.8175 

520 



615 


597 


614 


1,151 


* 88 (C-D 

-F, 0.813). 

*89 (C-D- 

E, 0.813).c 

*90(B-C-D ,0.8145) .c 

*91 (D-E, 0.815) .d 

A 

j 0.8035 

40 

0.8035 

130 

0.8065 

130 

0.801 

165 

A... 

l 


.807 

20 

.808 

27 

. 8025 

176 

T) 

J .808 

40 

.8077 

160 

.809 

137 

.8075 

206 


t 




.8115 

20 

.8085 

156 

P 

[ .8115 

73 

.8125 

330 

.813 

305 

.812 

330 


t • 813 

30 

.813 

60 

.815 

40 

.812 

512 


[ . 8155 

160 

.815 

550 

.815 

560 

.817 

340 

D . 



.8175 

90 

.8175 

75 

.817 

800 


l 






.817 

150 


/ .8195 

290 

.8175 

830 

.8175 

775 

.8215 

l O '79Q 


l 


.818 

425 

.818 

410 

etc. 

, i ou 



633 


2,595 


2,479 


5,568 


A. . 

B. . 

c.. 

D.. 

EF 


*92 (D-E, 0.8163). e 


0.805 
.8075 
.807 
.8115 
. 815 
.810 
.820 
.820 
.8225 
.8225 


84 

20 

100 

20 

205 

45 

350 

102 

500 

480 


1,906 


93 (F, 0.822). 


0.8107 

.810 

.814 

.816 

.8215 

.8285 

.831 


35 

43 

70 

25 

156 

250 

60 


639 


94 (F, 0.822). 


0.804 

.808 

.8165 

.817 

.8218 

.831 


28 

37 

03 

30 

146 

255 


559 


a Left. 
b Two tubes. 


c Four tubes. 
d Nine tubes. 


e Three tubes. 


To chill and filter these products of two fractionations would have 
entailed too much loss. As it was, much uniting of samples which 
differed but slightly from one another was necessary to obtain suffi¬ 
cient oil for further fractionation. A list of the unions which were 
made is given in Table 5. 























































































































FRACTIONATION IN TUBES. 

Table 5. Products of two fractionations united for the third fractionation. 


19 


Fractions united. 


Lot. 

Specific 

gravity. 

Grade. 

Specific 

gravity. 

Cubic 

centi¬ 

meters. 

Grade. 

Specific 

gravity. 

Cubic 

centi¬ 

meters. 

Grade. 

Specfic 

gravity. 

Cubic 

centi¬ 

meters. 



B 

0.8033 

48 

A 

0.8035 

240 

B 

0.8035 

25 

95.... 

0.805 

c 

. 8035 

63 

A 

.804 

65 

D 

.804 

140 


A 

. 8045 

150 

A 

.805 

360 

B 

.805 

95 



c 

. 805 

115 















1,251 

96.... 

.807 

1 £ 

.8058 

40 

A 

.806 

235 

EF 

.806 

275 


. .8065 

240 

B 

.8065 

100 

D 

. 8063 

180 



l A 

.807 

53 

C 

.807 

75 

C 

.8065 

92 











1,290 

97.... 

.8085 

I ? 

.808 

767 

C 

.808 

80 

A 

. 8083 

26 


1 A 

. 809 

20 

C 

.809 

210 

A 

.8085 

118 











1,221 

98.... 

.8085 

( A 

.8072 

20 

A 

. 8075 

290 

D 

.8075 

270 

1 A 

. 8077 

38 

B 

.8075 

480 













1,098 

99.... 

.8105 

1 £ 

.8105 

70 

A 

.8115 

21 

B 

.811 

580 


.811 

115 

A 

.811 

40 

C 

.8115 

73 



l c 

.8105 

270 

B 

.8115 

308 













1,477 

100... 

.8115 

EF 

.8113 

300 

EF 

.8115 

920 











1,220 




101... 

.8125 

C 

. .8123 

520 

D 

.8125 

160 

EF 

.8125 

820 











1,500 

103. 

.8135 

/ s 

.8125 

180 

B 

.813 

45 

C 

.8132 

60 


l B 

.8135 

106 

C 

.8135 

925 














1,316 

104... 

.814 

D 

• 

.8135 

370 

EF 

.8135 

715 











1,085 




106... 

.8145 

D 

• .814 

500 

C 

.8145 

910 











1,410 




112... 

.8175 

{ 8 

.8165 

.8175 

258 

200 

D 

.817 

425 

D 

.8172 

75 











958 

115... 

.819 

D 

.8175 

305 

D 

.818 

990 











1,295 




116_ 

.819 

EF 

.8185 

845 

EF 

.819 

683 











1,528 




120... 

.820 

D 

.8195 

475 

D 

.820 

600 











1,075 




123... 

.822 

EF 

.8215 

700 

D 

.8218 

460 

EF 

.822 

300 

126... 

.824 

D 

.823 

250 

EF 

.8235 

860 



1,460 

D 

.824 

140 

1,250 


No uniting was necessary for lots 102, 105, 107-111, 113, 114, 
117-119, 121, 122, 124, 125, and 127. In the third fractionation, 950 
cubic centimeters of each of these lots was filtered through earth 
again, with the results shown in Table 6. 




















































































































20 


FRACTIONATION OF CRUDE PETROLEUM 


Table (>.— Third fractionation. 



95 (A-D, 0.805). 

90 (A-EF, 0.807). 

97 (A-C, 0.8085). 

98 (A-D, 0.8085). 

Specific 

gravity. 

Cubic 

centi¬ 

meters. 

Specific 

gravity. 

Cubic 

centi¬ 

meters. 

Specific 

gravity. 

Cubic 

centi¬ 

meters. 

Specific 

gravity. 

Cubic 

centi¬ 

meters. 

A. 

0.8005 

33 

0.8045 

37 

0.800 

40 

0.8047 

38 

B. 

.805 

33 

.800 

38 

.8008 

40 

. 8052 

38 

p 

/ .804 

62 

.8005 

65 

.807 

58 

.808 

70 


\ .805 

40 

.8083 

25 

.8095 

18 

.8093 

30 

D. 

. 8055 

150 

.808 

142 

.8093 

154 

. 8095 

132 

EF. 

.808 

315 

.8095 

250 

.812 

295 

.811 

3:35 



633 


557 


005 


043 



99 (A-C 

0.8105). 

100 (EF, 0.8115). 

10*1 (C-EF, 0.8125). 

102 (C, 0.813). 

A. 

0. 8105 

.33 

0. 8005 

30 

0. 808 

33 

0.806 

26 

B. 

.810 

36 

.809 

36 

.8085 

34 

.8105 

33 

p 

[ .8075 

71 

.810 

60 

.811 

54 

. 8105 

50 


\ .8085 

17 

.812 

20 

.8145 

22 

.813 

17 

D. 

.811 

115 

.812 

130 

.8145 

102 

.813 

136 

EF. 

.814 

300 

.815 

315 

.817 

295 

.8157 

365 



572 


597 


000 


627 


103 (B-C, 0.8135). 

104 (D-EF, 0.814). 

105 (C, 0.814). 

106 (C-D, 0.8145). 

A. 

0.8065 

28 

0. 8042 

35 

0.804 

40 

0. 803 

33 

B. 

.810 

33 

.8115 

30 

.810 

40 

.810 

40 

P 

f . 8135 

00 

.8125 

00 

.8142 

58 

. 8145 

54 


\ .8165 

18 

.8147 

28 

.816 

25 

.816 

22 

D. 

.815 

150 

.815 

175 

.8103 

270 

.816 

150 

EF. 

.817 

325 

.819 

230 

.8185 

280 

.8185 

200 



614 


564 


713 


559 



107 (D 

0.815). 

108 (EF 

, 0.8155). 

109 (D, 0.8163). 

110 (D 

r-H 

OO 

d 

A. 

0. 8035 

45 

0.809 

52 

0.810 

. 33 

0.8065 

35 

B. 

.8115 

47 

.811 

47 

.8105 

45 

.8125 

40 

P 

f .815 

85 

.815 

55 

.8132 

55 

.817 

68 


\ .8177 

30 

.815 

40 

.8145 

33 

.818 

30 

D. 

.8175 

156 

.8165 

170 

.8185 

140 

.8195 

145 

EF. 

.8195 

300 

.8185 

255 

.8215 

275 

.821 

290 



663 


G19 


531 


608 


111 (EF, 0.817). 

112 (C-D 

, 0.8175). 

113 (EF, 0.8175). 

114 (EF, 0.8187). 

A. 

0. 8043 

30 

0. 8145 

35 

0.8065 

35 

0. 817 

30 

B. 

. 8105 

32 

.811 

32 

.812 

48 

. 8065 

25 

P 

f .8152 

65 

.8165 

60 

.8155 

75 

.8122 

30 


( .816 

43 

.818 

30 

.8175 

18 

.813 

15 

D. 

.8182 

160 

.819 

150 

.8185 

150 

. 8175 

150 

EF. 

.8205 

290 

.822 

245 

.8225 

283 

.822 

340 



620 


552 

* % 

609 


590 


115 (D, 0.819). 

116 (EF, 0.819). 

117 (D, 0.819). 

118 (EF, 0.819). 

A. 

0.8055 

16 

0. 8032 

30 

0.8045 

33 

0.805 

30 

B. 

.807 

Lost. 

.8115 

36 

.813 

38 

.813 

30 

n 

f .816 

43 

.816 

52 

.8175 

60 

.8165 

60 


\ .817 

30 

.820 

21 

.8175 

34 


10 

D. 

.820 

130 

. 8205 

160 

. 8215 

150 

.821 

154 

EF. 

.8225 

300 

.8235 

240 

.8235 

325 

.8243 

295 





539 


640 


579 





































































































































































FRACTIONATION IN TUBES 


21 


Table G. — Third fractionation — Continued. 



119 (EF, 

0.8195). 

120 (D, 

0.820). 

121 (EF 

0.821). 

122 (EF 

0.8215). 


Specific 

Cubic 

fpriti- 

Specific 

Cubic 

Specific 

Cubic 

Specific 

Cubic 


gravity. 

meters. 

gravity. 

meters. 

gravity. 

meters. 

gravity. 

meters. 

A. 

0.805 

23 

0.805 

33 

0.8075 

33 

0.803 

41 

13. 

.814 

35 

.811 

35 

.814 

41 

.811 

43 


f .8165 

58 

.817 

53 

.8182 

63 

.8165 

60 


l .8175 

32 

.8175 

35 

.819 

18 

.818 

23 

I). 

.8205 

152 

.822 

165 

.822 

150 

.8225 

182 

EF. 

.823 

300 

.825 

310 

.8245 

273 

.828 

270 



600 


633 


578 


629 



123 (D-EF, 0.822). 

124 (EF,0.8225). 

125 (EF,0.8235). 

126 (D-EF,0.824). 

127 (EF, 0.8255). 


Specific 

Cubic 

centi- 

Specific 

Cubic 

Specific 

Cubic 

Specific 

Cubic 

Specific 

Cubic 

CPTlti- 


gravity. 

meters. 

gravity. 

meters. 

gravity. 

meters. 

gravity. 

meters. 

gravity. 

meters. 

A. 

0.808 

34 

0.807 

31 

0.804 

35 

0.805 

35 

0.8055 

45 

13. 

.813 

35 

.8095 

27 

.813 

40 

.814 

35 

.8155 

40 


f . 8178 

52 

.8175 

65 

. 8185 

70 

.820 

60 

.821 

75 

c. 

1 .8192 

42 

.8185 

17 

.8195 

21 

.821 

20 

.823 

25 

D. 

. 8233 

155 

.8232 

150 

. 8252 

144 

.8253 

170 

.8275 

170 

EF. 

.8265 

260 

.8275 

300 

.829 

280 

.828 

300 

.830 

280 



578 


590 


590 


620 


635 


Sufficient oil of five grades for the fourth fractionation was obtained 
by uniting fractions from the third, as shown in Table 7. 


Table 7. —Products of three fractionations united for the fourth fractionation. 


128 


129 


130 


131 


Lot. 

Specific 

gravity. 

Fractions united. 

• 

Lot. 

Grade. 

Specific 

gravity. 

Cubic. 

centi¬ 

meters. 

Lot. 

Grade. 

Specific 

gravity. 

Cubic 

centi¬ 

meters. 



99 

EF 

0.814 

300 

100 

EF 

0.815 

315 



101 

C 

. 8145 

22 

101 

D 

.8145 

162 



103 

D 

.815 

150 

104 

C 

.8147 

28 


0.815 

104 

D 

.815 

175 

105 

C 

.8142 

58 



106 

C 

.8145 

54 

107 

C 

. 815 

85 



108 

C 

.815 

55 

108 

C 

.815 

40 



. 109 

c 

.8145 

33 

111 

C 

.8152 

65 










1,542 



1 101 

EF 

.817 

295 

105 

D 

.8163 

270 


.8163 

{ 102 

EF 

. 8157 

365 

106 

D 

.816 

150 



{ 103 

EF 

.817 

325 

108 

D 

.8165 

170 










1,575 



1 104 

EF 

.819 

230 

108 

EF 

.8185 

255 


.819 

^ 105 

EF 

.8185 

280 

113 

D 

.8185 

150 



| 106 

EF 

.8185 

260 

109 

D 

. 8185 

140 










1,315 



107 

EF 

.8195 

300 

115 

D 

.820 

130 



no 

D 

.8195 

145 

116 

D 

. 8205 

160 


. 8205 

111 

EF 

.8205 

290 

118 

D 

.821 

154 



119 

EF 

. 8205 

152 














1,467 



1 113 

EF 

.8225 

283 

120 

D 

.822 

165 


.823 

{ 115 

EF 

. 8225 

300 

121 

D 

.822 

150 



l 119 

EF 

.823 

300 

122 

D 

.8225 

182 










1,380 


* 


132 





















































































































F R ACTION AT I ON OF CRUDE PETROLEUM. 



The results of the fourth fractionation are stated in Table 8. 


Table 8. —Fourth fractionation. 



228 

(C-EF, 0.815). 

129 

(D-EF, 0.8168). 

130 

(D-EF, 0.819). 

131 

(D-EF, 0.8205). 

132 

(D-EF, 0.823). 


Specific 

Cubic 

nent-i- 

Specific 

Cubic 

eont.j- 

Specific 

Cubic 

eent.i- 

Specific 

Cubic 

Cf>nt.i- 

Specific 

Cubic 

centi 


gravity. 

meters. 

gravity. 

meters. 

gravity. 

meters. 

gravity. 

meters. 

gravity. 

meters. 

A. 

0.8135 

19 

0.812 

30 

0.8115 

24 

0.8095 

18 

0.8092 

35 

B. 

.815 

27 

.8122 

42 

.8127 

35 

.813 

26 

Lost. 

35 


f .8118 

50 

.8165 

55 

.8173 

60 

.819 

45 

. 8195 

60 

L. 

\ .813 

15 

.818 

25 

.8185 

22 

. 8195 

17 

.8213 

25 

i) . 

.8147 

140 

.818 

160 

.820 

160 

.8215 

130 

.8235 

150 

EF. 

.8175 

360 

.8195 

305 

.8215 

310 

.824 

340 

.826 

280 



611 


617 


611 


576 


585 


To better compare the oils of different specific gravities that were 
obtained by the process just described each of six 300 cubic centi¬ 
meter samples (five of partly refined oil and one of crude petroleum) 
was separated by distillation into ten fractions. Each sample was 
distilled in the same 500 cubic centimeter distilling bulb, which was 
heated by an electric stove that entirely surrounded it. The oil was 
first heated to 200° under atmospheric pressure and then to 360° 
under a pressure of 50 millimeters. The diminished pressure was 
obtained with a large Chapman water pump and kept constant by 
the use of a valve which automatically admitted air to the evacuated 
system whenever the pressure fell below 50 millimeters. This valve 
was constructed from a piece of iron pipe 1 inch in diameter and 5 
feet long. The lower end was closed with a cap and the pipe filled 
with mercury to a depth of 76 centimeters. The upper end of the 
pipe was closed with a two-hole rubber stopper. In one hole was a 
long glass tube with the lower end beveled, which reached to the 
bottom of the mercury and could be raised or lowered as the barom¬ 
eter varied from day to day. In the other hole was a tube which 
passed just through the stopper and was connected on the outside 
with the apparatus to be exhausted. To prevent mercury from 
being drawn up and over into the apparatus by the air admitted, the 
end of the tube inside the stopper was drawn out and bent at a right 
angle and over this was slipped a cap made of larger tubing closed at 
the bottom, but having a fine opening in the side for air. This cap was 
about 6 centimeters long and extended about 3 centimeters below 
the end of the tube inside. If any mercury passed through this first 
fine opening into the cap, it would fall to the bottom without being 
drawn over into the apparatus or clogging the fine opening in the 
tube leading thereto. With this valve there was no difficulty in 
keeping a pressure of 50 millimeters constant within 1 millimeter. 










































FRACTIONATIOX IN TUBES. 


23 


Each distillate of sufficient volume, which was not too viscous or 
partly solid, was tested as to specific gravity, viscosity, and percentage 
absorbed when treated with concentrated sulphuric acid (specific 
gravity 1.84). 

Tab l*e 9. —Fractionation of six samples by distillation. 


Specific gravity. 

Viscosity. 

Tubes passed through. 


Normal pressure: 


Below 150°.. 


150°-200°_• 


Specific gravity.. 

Viscosity. 

Void treatment^ Per cent absorb 
aciu treatment j gpeciflc gravity 


Specific gravity. 
Viscosity. 


50 mm. pressure: 


l \Specific gravity. 


Below 140°. .■ 


140°-200° 


200°-230°. 


230°-260°.. 


2(i0 o -300 o .... 


300°-340°. 
340°-300°. 
Residue.. 


Specific gravity. 
Viscosity. 


\cid trpatTnend Per cent absorbed. 
Acid treatment lSpecific gravity 


Specific gravity. 
Viscosity. 


Specific gravity.. 

Viscosity.. 

Acid treatment! P £L^ n hl h 51 r ! )ed ' 


Specific gravity. 
Viscosity. 


'1 Specific gravity. 


Specific gravity. 

Viscosity. 


Specific gravity. 

Amount. 

^Specific gravity. 

Amount. 

Specific gravity. 


Total volume.cubic centimeters.. 


]. 

2. 

3. 

4. 

5. 

6. 


0.801 

0.808 

0.815 

0 8195 

0.824 

0.810 


0.0404 

0.0555 

0.0589 


0.0657 

0.0441 


1 

3 

3 

4 

4 

Crude 







oil. 


36 

1 

13 

5 

2 

45 


0.720 


0.737 



0.714 


0.0052 


0.0059 



0.0047 


4.4 





8.6 


0.722 

. 

0.7365 



0.712 


47 

61 

52 

60 

60 

43 


0.749 

0.7465 

0.756 

0.757 

0.759 

0.759 


0.0075 

0.0073 

0.0075 

0.0073 

0.0072 

0.0076 


3.4 

4.4 

8.2 

11.3 

12.0 

9.3 


0.749 

0.7469 

0.750 

0.749 

0.750 

0.752 


10 

9 

3 

6 

10 

19 







0.7805 







0.0112 







11.9 







0.7735 


69 

75 

80 

80 

73 

48 


0.790 

0.790 

0.797 

0.800 

0.8015 

0.804 


0.0212 

0.0185 

0.0211 

0.0216 

0.0196 

0.0254 


3.4 

4.4 

8.9 

9.6 

14.8 

11.0 


0.790 

0.7885 

0.7915 

0.795 

0.7915 

0.799 


25 

30 

23 

25 

30 

21 


0.813 

0.8135 

0.818 

0.8225 

0.822 

0.823 


0.0556 

0.0594 

0.0573 

0.0661 

0.0505 

0.0593 



4.3 

11.0 

8.4 

10.5 

8.7 


0.813 

0.8125 

0.816 

0.8217 

0.818 

0.8175 


23 

27 

23 

20 

24 

22 


0.8255 

0.826 

0.830 

0.833 

0.838 

0.8355 


0.1106 

0.1150 

0.1116 

0.1168 

0.1259 

0.1284 


3.4 

8.5 

7.0 

8.8 

7.6 

12.6 


0.8255 

0.8255 

0.828 

0.832 

0.833 

0.830 


20 

22 

23 

24 

20 

17 


0.8395 

0.838 

Fluid. 

Fluid. 

Fluid. 

Fluid. 


0.2520 







25 

a 30 

27 

30 

26 

25 


0.847 

0.849 

Solid. 

Solid. 

Solid. 

Solid. 


21 

« 26 

22 

. 

19 

20 


Fluid. 

Fluid. 

Fluid. 


Fluid. 

Fluid. 


22 

17 

30 

45 

35 

32 


Fluid. 

Fluid. 

Fluid. 

Fluid. 

Fluid. 

Fluid. 


298 

298 

296 

295 

299 

292 


a To 355°. 


Viscosity was measured by taking the time of flow of a measured 
volume of oil through a capillary, the viscometer used being the one 
described bv Ostwald and Luther as modified by Jones and Veazey.® 
The capacity of the small bulb was 4.5 cubic centimeters and the diam¬ 
eter of the capillary such as to require from five to eight minutes for 
that amount of oil to flow through it, and 1 minute 2.0 seconds for the 
same amount of water. The viscosity as well as the specific gravity 
was always measured at a temperature of 20° C. Viscosities have 


TS 

been calculated from the formula ij = ij 0 qvg 


in which ij G is the coef- 


« Zeitschr. pliysikal. Chemie, vol. 61, p. 651. 



















































































24 


FRACTIONATION OF CRUDE PETROLEUM. 


O 

> 


70 


60 


50 


40 


30 


20 


10 



ficient of viscosity for water, S c is the specific gravity of water, and 
T 0 the time of flow of water through any given capillary at a given 
temperature; ij is the viscosity coefficient of the solution investi¬ 
gated, S is its specific gravity as compared with water as unity at 

any given temperature, and 
T is the time of flow of the 
given solution at that tem¬ 
perature. The value for 
pure water at 20° was taken 
from the work of Thorpe 
and Kodger . a 

Thirty cubic centimeters 
of each of these distillates 
where that much oil was 
available, or all the oil 
there was where the vol¬ 
ume was less than 30 cubic 
centimeters was mixed with 
an equal volume of concen¬ 
trated sulphuric acid (spe¬ 
cific gravity 1.84) and 
shaken for half an hour or 
longer in a shaking ma¬ 
chine. The oil and acid 
were then poured into a 
separating funnel and the 
acid drawn off. The oil 
was then washed twice with 
water, once with aqueous 
NaOH, again with water, 
and then with this last 
wash water poured into a 
burette and allowed to set¬ 
tle. After standing over¬ 
night the volume was read. 

The oils boiling below 200° 
(at 50 millimeters pressure) 
separated clear, but the 
heavy distillates were milky 
from water. The volume 
of these milky oils was read, their specific gravity was taken, and 
then the milkiness was removed by shaking and heating to about 
60° with ( a( 1 2 . I he specific gravity of the clear oil was then taken 
and the proper correction made to the milky volume. In no case, 







/ 









( 2 ) 





























150 C 

-V- 


200° .140° 200° 230° 260 c 


—-V- 

Normal pressure 50 mm. pressure 

TEMPERATURE 

Fig. 1 . —Curves showing proportion of hydrocarbons sol¬ 
uble in sulphuric acid, oils 1 and 2. 


“Phil. Trans., vol. 185A, 1894, p. 397. 
































FRACTIONATION IN TUBES. 


25 



LU 

Z> 

_J 

O 

> 


70 


60 


50 


40 


30 


20 


10 


however, was this correction large, and only for the three or four 
heaviest oils did it exceed one-half of 1 per cent, the largest correc¬ 
tion of all being 2.6 per cent for the distillate between 230° and 260° 
of the oil of specific gravity 0.824. An attempt to treat with acid 
the oils selected to be dis¬ 
tilled resulted in so much 
loss from the formation of 
emulsions that the loss in 
volume and change in spe¬ 
cific gravity could not be 
determined with any degree 
of accuracy. 

The results of the distil¬ 
lation of these samples are 
summarized in Table 9. 

“Fluid” means that the 
oil at 20° was partly solid, 
but would flow when the 
bottle was inclined; ‘ 1 solid ” 
means that the oil would 
not change its shape when 
the bottle was turned upside 
down. 

It was hoped that sulphu¬ 
ric acid of the strength used 
would dissolve only unsat¬ 
urated hydrocarbons and 
leave untouched the paraf¬ 
fins and benzene. By long- 
continued shaking at ordi¬ 
nary temperatures, however, 
with acid of this strength 
benzene is dissolved, pro¬ 
vided that the acid is in large 
excess. On being shaken for 
four hours 100 cubic centi¬ 
meters of benzene was com¬ 
pletely dissolved in 434 cu¬ 
bic centimeters of acid. 

Three of the distillates 
which had been shaken with acid showed no action when treated with 
a mixture of equal parts of concentrated sulphuric acid and fuming 
nitric acid, whereas this nitrating mixture did act on distillates which 
had not been previously shaken with sulphuric acid. The action of 
the sulphuric acid, therefore, appears to have been complete. 
















(4) 





























.o c 


150 

-V- 


200° 140° 200° 230° 260 c 


Normal pressure 50 mm. pressure 

TEMPERATURE 

Fig. 2.—Curves showing proportion of hydrocarbons sol¬ 
uble in sulphuric acid, oils 3 and 4 . 

































26 


FRACTIONATION OF CRUDE PETROLEUM. 


The results of the acid treatment showed that over 90 per cent of the 
oil used consisted of paraffin hydrocarbons, and that in the filtration 
through earth the paraffin hydrocarbons tended to collect at the top 
of the tube and the unsaturated hydrocarbons at the bottom. 

The increasing amount 


increasing 

dissolved by sulphuric acid 
in the heavier oils may be 
seen in the curves shown 
in figs.l to 3. The abscis¬ 
sas represent temperatures 
and the ordinates volumes. 
The same distance on the 
x axis is taken to represent 
a distillate, whatever be 
the number of degrees over 
which it may have been col- 
lected. The upper curve 
represents the percentage 
of the total volume that 

distilled between triven 

© 

temperatures; the lower 
curve the percentage of 
the total volume recovered 
that was not absorbed by 
sulphuric acid (that is, the 
par affi n hydrocarbons). 
For the upper curve the 
ordinates are obtained by 
dividing the number of 
cubic centimeters in the 
distillate by the total vol¬ 
ume of oil recovered. For 
the lower curve the ordi¬ 
nates are obtained by 
dividing the number of 
cubic centimeters in the 
distillate not absorbed by 
sulphuric acid by the total 
volume of oil recovered. 
The area between the two curves represents the proportion of hydro¬ 
carbons soluble in sulphuric acid. It will be seen that this is greatest 
for the oils of highest specific gravity. 

1 ables 4 and 6 show that in several tubes the specific gravitv of the 
oil of grade A was greater than that of the grade B oil and in some 



150° 200° 140° 200° 230° 260° 


Normal pressure 50 mm. pressure 

TEMPERATURE 

Fig. 3.—Curves showing proportion of hydrocarbons solu¬ 
ble in sulphuric acid, oils 5 and 6. 
































FRACTIONATION IN TUBES. 


27 


tubes than that of the grade C oil. This irregularity was marked in 
tubes 48, 62, 68, 72, 74, and 80 of Table 4 and 112 and 114 of Table 6. 
A slight irregularity appears in tubes 20, 21, 24, 27, 40, 71, and 85 of 
Fable 4 and tube 99 of Table 6. Of the oils in these tubes that were 
not colorless the color was strongest where the specific gravity was 
greatest, so that although the oil of grade A had passed through 
the most earth it was yet more strongly colored than that of grade B 
or C. 

No reason for this variation has been established. It should be 
remembered, however, that the different oils rise in the earth with 
differing velocities, not because they differ from one another in spe¬ 
cific gravity, but because they differ in surface tension. A rough 
attempt was made to determine relative surface tensions by measur¬ 
ing the height to which different oils rise in the same capillary tube, 
but although a kathetometer was used and the level of the oil in the 
capillary brought to the same spot each time the work sufficed only 
to show that the difference in the surface tension of the oils was so 
slight as to require very careful measurement to obtain results of any 
value. 

That the viscosity shows the same irregularity in these oils as color 
and specific gravity appears from the following measurements: 


Table 10. —Specific gravity and viscosity of fractions from tubes 62 and 68. 



62. 

68. 

Specific 

gravity. 

Viscos¬ 
ity. * 

Specific 

gravity. 

Viscos¬ 

ity. 

A . 

0.8155 
.808 
j .8095 

1 .812 
/ .8175 

\ .8182 
.823 

0.0539 
. 0469 
.0509 
.0555 
.0525 
.0535 
.0612 

0.8205 
.8043 
.810 
.812 
.817 

. 8225 

0.0626 
.0469 
.0520 
.0554 
.0524 

. 0606 

B . 

C . 

D . 

E F . . 



Tube 50 (Table 4) showed an irregularity in grade B, which is also 
found in the viscosity: 

Table 11. —Specific gravity and viscosity of fractions from tube 50. 



Specific 

gravity. 

Viscos¬ 

ity. 


0.8105 

0.0532 


.8148 

.0559 


.810 

.0526 


.815 

.0526 


.819 

.0552 



_ 


The oils obtained by one fractionation of the crude petroleum (see 
Table 1) had the following viscosities: 



































28 


FRACTIONATION OF CRUDE PETROLEUM. 


Table 12 .—Specific gravity and viscosity of fractions from tubes 1 to 3. 



1 

• 

2. 

3. 

Specific 

gravity. 

Viscos¬ 

ity. 

Specific 

gravity. 

Viscos¬ 

ity. 

Specific 

gravity. 

Viscos¬ 

ity. 

A. 

0.796 

0.0376 

0.8012 

0.0408 

0.8022 

0.0401 

B. 

.808 

.0529 

.804 

.0485 

.803 

. 0470 


( .8125 

.0501 

.807 

. 0443 

.8075 

.04.53 


\ .8137 

.0529 

.809 

.0476 

.810 

. 0471 

D. 

.815 

. 0504 

.8125 

.0460 

.812 

.0472 


.818 

.0521 

.8185 

.0537 

.8175 

.0529 

F. 

.8205 


.823 


.821 



That the viscosity does not increase with the specific gravity, par¬ 
ticularly in the higher fractions, is apparent in two of the three series 
just given. The same is also shown in four tubes whose records are 
given in Table 4. 


Table 13 .—Specific gravity and viscosity of fractions from tubes 21, 22, 47, and 53. 



21. 

22. 

47. 

53. 

Specific 

gravity. 

Viscos¬ 

ity. 

Specific 

gravity. 

Viscos¬ 

ity. 

Specific 

gravity. 

Viscos¬ 

ity. 

Specific 

gravity. 

Viscos¬ 

ity. 

A. 

0.8038 

0.0465 

0.7997 

0.0421 

0.800 

0.0453 

0.803 

0.0515 

B. 

. 8035 

.0456 

.802 

.0485 

.807 

.0538 

.8105 

.0563 

P 

| .8035 

.0456 

.8055 

.0502 

.814 

.0542 

.815 

.0684 


1 .8052 

.0485 







D. 

.805 

.0479 

.8063 

.0496 

.816 

.0528 

.8185 

.0570 

EF. 

.807 

.0480 

.808 

.0510 

.819 

. 0556 

.820 

.0559 


This drop in viscosity which occurs at the bottom of the tube 
appears to be a regular occurrence in the dozen or so oils which 
have been tested. Further investigation of this point is intended. 


WATER FRACTIONATION. 

To test the effectiveness of water fractionation alone, 1,000 cubic 
centimeters of crude petroleum, previously chilled and filtered, of 
specific gravity 0.807, was mixed with 1,000 grams of earth and 
allowed to stand for twenty-four hours. Water was then added in 
small amounts and the oil collected. The results are stated below. 


Table 14 .—Fractionation of crude petroleum with water. 



Specific 

gravity. 

Cubic 

centi¬ 

meters. 

Total 
water 
present 
(cubic 
centi¬ 
meters) . 

A. 

0.8148 
.8139 
.816 
.820 
.8225 
- 8243 

44 

278 

211 

84 

28 

'28 

673 

.500 

650 

800 

950 

1,400 

2,750 

B. 

C. 

D.. 

E. 















































































WATER FRACTIONATION. 


29 


The fractions of large enough volume were then mixed with earth 
again and the oil replaced with w r ater. One gram of earth w^as used 
for each cubic centimeter of oil, the earth having been heated and 
allowed to cool. Table 15 shows the results. 

Table 15. —Second fractionation of petroleum with water. 



B. 

C. 

D. 

Specific 
gravity.. 
Cubic cen¬ 
timeters. 
Time (hrs.) 

0.8139 

278 

1.5 

0.816 

211 

6 


0.820 

84 

2.5 



Specific 

gravity. 

Cubic 

centi¬ 

meters. 

W ater 
(cubic 
centi¬ 
meters) . 

Specific 

gravity. 

Cubic 

centi¬ 

meters. 

W ater 
(cubic 
centi¬ 
meters) . 

Specific 

gravity. 

Cubic 

centi¬ 

meters. 

Water 
(cubic 
centi¬ 
meters) . 

1. 

0.8185 

10 

70 

0.820 

10 

80 

0.822 

32 

76 

2. 

.818 

10 

110 

.820 

20 

125 

.823 

20 

207 

3. 

.818 

21 

164 

.8195 

72 

250 




4. 

.818 

20 


.820 

30 

410 




5. 

.817 

42 


.820 

10 

588 




6. 

.819 

10 

216 




7. 

.820 

44 

277 







8. 

.820 

16 

428 







9. 

.8215 

20 

686 









193 



142 



52 



It is apparent that while petroleum is fractionated by simply mixing 
the oil with fuller’s earth and then displacing the oil from the earth 
with water, the fractionation is much more complete when tubes are 
used, as previously described. 

It will be noticed that although fractions C and D of Table 14 are 
separated hardly at all by further treatment with earth and wrater 
(Table 15), yet the specific gravity of all the oil recovered is higher 
than that of the oil used; for example, fraction C (specific gravity 
0.816) yields nothing lighter than 0.8195, and 1) (specific gravity 
0.820) nothing lighter than 0.822. 

To determine whether the specific gravity of the oil recovered will 
continue to rise after the oil is fractionated no further by repeated 
treatment, 330 cubic centimeters of specific gravity0.819,obtained by 
uniting several products of one fractionation of the crude petroleum, 
were mixed with 330 grams of earth, and water was added, as shown in 
Table 16. 


Table 16. —Second fractionation of petroleum (combined sample) with water. 



Specific 

gravity. 

Cubic 

centi¬ 

meters. 

Total 

water 

present 

(cubic 

centi¬ 

meters). 



6 

64 

B . 

0.8215 

50 




12 

214 

D . 

.821 

60 

270 

E . 

.821 

82 

413 

F . 

.8225 

26 

613 



236 







































































30 


FRACTIONATION OF CRUDE PETROLEUM. 


When 75 cubic centimeters of fraction E (specific gravity 0.821) 
was next mixed with 75 grams of earth and 150 cubic centimeters of 
water was added, 51 cubic centimeters of oil whose specific gravity 
was unchanged, but whose color was reduced, was obtained. Fifty 
cubic centimeters of this oil when treated with earth and water, 
returned 34 cubic centimeters of oil with the color considerably 
lighter, but with the specific gravity still 0.821. 

Although only two-thirds of the oil used is recovered when oil is 
mixed with earth and then displaced with water, yet this loss does not 
seem to affect the specific gravity of the oil obtained except in the 
first one or two treatments after the oil ceases to be fractionated. 
After these first treatments the oil recovered has the same specific 
gravity as the oil used. 

OIL LOST IN THE FULLER*S EARTH. 

The sum of the fractions of oil displaced from the earth is as a rule 
only about two-thirds of the volume of the oil used: A pressure of 
approximately 200 tons per square inch on the earth from which 
water has displaced all oil that it will results in the liberation of con¬ 
siderable water but very little oil. When earth which has been 
pressed is heated to 165° for three hours, considerable water distills 
over, but much less oil than would be expected; for example, from 75 
grams of earth which should contain 25 cubic centimeters of oil only 
4 cubic centimeters of oil was obtained. The earth was removed 
once from the flask and pulverized, and when the heat was discontin- * 
ued the earth was thoroughly dry. On extraction with ether in a 
Soxlet extractor the earth gave a solution having the color of the 
original petroleum. The extraction was continued until the extract 
was colorless. On evaporation of the ether there remained about 8 
cubic centimeters of a heavy oil with the color of the natural petroleum. 
Pressure, heat, and extraction with ether together gave about half the 
amount of oil which the earth must have contained. 

Earth that had been used once was allowed to dry for several weeks 
at room temperature until it had lost all appearance of containing 
moisture. It was then pulverized, sifted, and 720 grams used in a 
tube with 740 cubic centimeters of the crude petroleum of specific 
gravity 0.810, with the following results: 


Table 17 . — Fractionation of crude petroleum with earth that had been used once. 



Specific 

gravity. 

Cubic 

centi¬ 

meters. 

8 centimeters at top. 


0 

Next 8 centimeters. 

0.8284 

10 

Next 18 centimeters. 

.8225 

45 

Next 30 centimeters. 

/ .8143 

60 


l .8155 

80 


j .8175 

83 


\ • 819 

114 


• 

392 

















OIL LOST IN FULLER'S EARTH. 


31 


The first oil up the tube is evidently absorbed by heavy material in 
the earth; the first oil recovered dissolves material from the earth, 
which increases its specific gravity beyond that of the next fraction. 

To see how much of the weight of the earth used the second time 
was due to material which it had retained from its first use, 300 grams 
of earth was mixed with 300 cubic centimeters of crude petroleum and 
the oil displaced by water. The oil recovered measured 205 cubic 
centimeters, and the weight of the earth after drying for several weeks 
at room temperatures was 347.5 grams. Fully 15 per cent, therefore, 
of the weight of the earth used the second time was solid matter 
which it had retained from its first use. 

In all tests the earth was heated before it was used because it was 
believed that heating decreased the amount of oil lost in the earth. 
The earth was heated usually in iron pans on a gas stove until it 
ceased to form geysers when stirred. A tube 5 feet long and 11 inches 
in diameter, packed with 948 grams of earth that had not been heated, 
gave results as follows with 930 cubic centimeters of crude petroleum 
of specific gravity 0.810, after standing for twenty hours at dimin¬ 
ished pressure: 


Table 18. —Fractionation of crude 'petroleum with earth that had not been heated. 



Specific 

gravity. 

Cubic cen¬ 
timeters. 

Top 8 centimeters. 

0.803 

.8045 

.8103 

30 
. 38 

85 
440 

Next 8 centimeters. 

Next 18 centimeters. 




593 


In a test of water fractionation alone with unheated earth but 242 
cubic centimeters of oil was recovered from 500 cubic centimeters of 
crude petroleum. 

The results obtained toward the close of our work indicate that the 
loss of oil when unheated earth is used is much less than we had sup¬ 
posed it to be. The gain from heating the earth may not pay for the 
trouble of heating it, and this point should be investigated before 
any very extensive experiments are again undertaken. 

Earth after heating must become thoroughly cold before it is used 
to pack tubes. The earth holds its heat for several hours, and if it is 
used the same day on which it is heated, there is apt to be sufficient 
contraction in the tube to allow the oil to run up the side as it would 
in a vacuum. 

The length of the tubes used was 5J feet. A tube 9 feet long was 
connected to the same vacuum pump with several 54-foot tubes and 
held for two days with a constant diminished pressure of about 10 
centimeters Ilg. The oil was drawn to the top of the shorter tubes; 
these v r ere removed and a second lot substituted, and these also were 

















32 


FRACTIONATION OF CRUDE PETROLEUM. 


fully impregnated with oil before the long tube was opened. When 
it was opened the oil had ascended but 45 centimeters, showing that 
the diminished pressure had not penetrated the 9 feet of earth and 
reached the bottom of the tube. 

A shorter tube in which the earth was packed very much harder, 
so that it rang like an iron rod when pounded on the floor, was con¬ 
nected with a vacuum pump at one end and a manometer at the other, 
and showed diminished pressure on the manometer when the column 
of earth was 2 feet long but not when it was 2 feet 4 inches. 

FRACTIONATING POWER OF SUBSTANCES OTHER THAN FULLER^ EARTH. 


A clay from Topsham, Me., showed in tubes a power of fractionating 
as well as of decolorizing the higher fractions. Tubes 5 feet long and 
11 inches in diameter were used, with petroleum of specific gravity 
0.806. Compared with fuller’s earth, the action was as follows: 

Table. 19. —Fractionation of crude petroleum with, clay from Topsham, Me., and with 

fuller's earth. 


8 centimeters at top 
Next 8 centimeters. 
Next 8 centimeters. 
Next 10 centimeters 
Next 30 centimeters 
Next 45 centimeters 
Time required. 


specific gravity 

..do.. 

.. do.. 

..do.. 

..do.. 

..do.. 

.hours 


Clay. 

Fuller’s 

earth. 

0.799 

0.793 

.804 

.800 

.810 

.806 

.810 

.807 

.812 

.8092 

.812 

.8112 

69 

76 


Neither powdered brick made from the same clay nor powdered 
feldspar showed any power of fractionation. 

Another similar clay (from Mere Point, Brunswick, Me.) showed a 
power of water fractionation, but its behavior in a tube was not 
tested. Four hundred grams of this clay, previously sifted and 
heated, was mixed with 170 cubic centimeters of crude petroleum of 
specific gravity 0.806 and allowed to stand for fourteen hours. Water 
was then added and the following fractions were obtained: 

Table 20. —Fractionation of crude petroleum with clay from Brunswick, Me. 



Specific 

gravity. 

Cubic cen¬ 
timeters. 

Total 

water 

present 

(cubic 

centime¬ 

ters). 

# 

A. 

0.8165 

24 

104 

B. . 

. 817 

60 

133 

C. 

.8188 

20 

234 

D. 

6 

374 



110 


The color was scarcely changed at all. 









































FRACTIONATION OF CRUDE PETROLEUM. 


33 


SUMMARY. 

1. When petroleum is allowed to rise in a tube packed with fuller’s 
earth, there is a decided fractionation of the oil, the fraction at the 
top of the tube being of lower specific gravity than that at the bottom. 

2. When water is added to fuller’s earth which contains petroleum, 
the oil which is displaced first differs in specific gravity from that 
which is displaced afterward, when more water is added. 

3. When petroleum is allowed to rise in a tube packed with fuller’s 
earth, the paraffin hydrocarbons tend to collect in the lightest fraction 
at the top of the tube and the unsaturated hydrocarbons at the 
bottom. 

4. When oil is mixed with fuller’s earth and then displaced with 
water, about one-tliird of the oil remains in the earth. 


O 


































